decorated curry

curry.js

const meta = Symbol('@@ramda-meta');

const initMeta = f => ({ func: f, arity: f.length, seenArgs: [] });

const getMeta = f => f[meta] || initMeta(f);

const setMeta = (arg, f) => {
  const fMeta = getMeta(f);
  f[meta] = {
    func: fMeta.func,
    arity: fMeta.arity - 1,
    seenArgs: fMeta.seenArgs.concat(arg)
  };
  return f;
};

const _curryN = (n, f) => {
  const fMeta = getMeta(f);
  
  const curried = a => {
    const recurried = setMeta(a, _curryN(fMeta.arity - 1, curried));
    return (recurried[meta].arity === 0 
            ? recurried[meta].func.apply(null, recurried[meta].seenArgs)
            : recurried
           );
  };
  curried[meta] = fMeta;
  
  return curried;
};

example.js

// abc :: (String, String, String) -> String
function abc(a, b, c) {
  return '' + a + b + c;
}

const cabc = _curryN(3, abc); // cabc :: String -> String -> String -> String 

const gotA = cabc('A'); // gotA :: String -> String -> String 

const gotAB = gotA('-B-'); // gotB :: String -> String

const gotABC = gotAB('C!'); // gotABC :: String 'A-B-C!'